Help: Gotoubun no hanayome natsu no omoide .psb files exm2lib

[Artoria Pendragon]

I'm using exm2lib to decrypt the .psb files in gotoubun no hanayome natsu no omoide but I don't know where to insert the key so it's saying that there's access violation. I tried replacing it with the key in .cpp files but when I try to compile it there's an error. Anyone knows what should I do?